Power storage modules for vehicles such as electric cars and hybrid cars have an array of a plurality of batteries (power storage elements) with positive and negative electrode terminals. The electrode terminals of the adjacent batteries are connected together by bus bars included in a connection module such that the plurality of batteries are connected in series or in parallel.
To connect the plurality of batteries in series, in general, the electrode terminals of the two each adjacent power storage elements in one line are connected together by a bus bar corresponding to the one line in the connection module. In the other line, the electrode terminals of the two each adjacent batteries shifted in position by one battery from the two each adjacent batteries connected in the one line are connected together by a bus bar corresponding to the other line in the connection module.
As such a connection module, there is known a flat-shaped connection module that is simple in structure and is reduced in weight (for example, refer to Patent Document 1). Patent Document 1 discloses a technique for firmly coupling voltage detection lines and flat-plate conductors (bus bars) in a flat-shaped bus bar module (connection module) including the voltage detection lines and the flat-plate conductors.